Table 1 The characteristics of all participants

Mean age (years old)

62 ± 6

58 ± 4

1.957

0.055

Gender, male, n (%)

72 (94.7%)

58 (93.5 %)

0.088

0.767

Height (cm)

168.3 ± 7.1

169.8 ± 5.8

− 1.318

0. 190

Weight (kg)

72.1 ± 11.2

71.7 ± 7.4

0.203

0.839

BMI (m/kg²)

25.0 ± 2.7

24.9 ± 2.3

0.294

0.769

Pulmonary function

 FVC % predicted

80.9 ± 14.5

105.9 ± 14.1

− 10.229

< 0.001^*

 FEV1% predicted

82.4 ± 14.4

100.3 ± 12.2

− 7.775

< 0.001^*

 FEV1/FVC% predicted

81.4 ± 6.1

81.7 ± 8.8

− 0.236

0.814

 TLC % predicted

67.7 ± 11.1

99.2 ± 13.9

− 14.753

< 0.001^*

 DLCO % predicted

54.8 ± 15.2

102.3 ± 18.1

− 16.801

< 0.001^*

 CPI

39.1 (32.4, 48.1)

5.6 (− 8.0, 13.7)

− 9.845

< 0.001^*

 6-MWD (m)

462.7 ± 67.1

\

Resting dyspnea (MRC), n (%)

 0

0

\

 1

24 (31.6%)

\

 2

34 (44.7%)

\

 3

12 (15.8%)

\

 4

6 (7.9%)

\

HRQoL

 Respiratory symptoms (%)

51.5 (32.1, 63.5)

\

 Activity (%)

42.1 (27.6, 55.6)

\

 Psychosocial impact (%)

16.9 (7.8, 28.4)

\

 Total (%)

31.1 (14.9, 40.4)

\

The percentage of pulmonary fibrosis on HRCT

 Pulmonary fibrosis (%)

8.3 (4.8, 16.3)

\

Pulmonary vascular-related indexes

 TPV volume (ml)

181.22 (160.61, 219.29)

194.56 (182.75, 211.33)

− 1.627

0.104

 TPV number

1706 (1422, 2185)

2716 (2414, 2998)

− 8.408

< 0.001^*

 TPV tortuosity

1.12 (1.09, 1.18)

1.07 (1.05, 1.08)

− 8.396

< 0.001^*

 PVV volume (ml)

94.55 (80.44, 114.72)

95.78 (86.74, 99.98)

− 0.634

0.526

 PVV number

930 (722, 1139)

1320 (1190, 1478)

− 6.353

< 0.001^*

 PVV tortuosity

1.11 (1.08, 1.16)

1.07 (1.05, 1.08)

− 7.087

< 0.001^*

 PAV volume (ml)

90.20 (78.32, 105.80)

99.37 (92.05, 113.25)

− 2.877

0.004

 PAV number

805 (550, 956)

1352 (1173, 1476)

− 9.487

< 0.001^*

 PAV tortuosity

1.12 (1.10, 1.12)

1.06 (1.05, 1.08)

− 8.194

< 0.001^*